The present invention relates to a control system that performs a control of a hybrid vehicle drive system that includes: an input member that is drivingly connected to a rotary electric machine; a clutch that selectively and drivingly connects the input member to an internal combustion engine; an output member that is drivingly connected to a wheel; and a speed change mechanism that has a plurality of shift speeds selectively formed by controlling the engagement and disengagement of a plurality of engagement elements, and changes a rotational speed of the input member by a speed ratio of the respective shift speeds and transmits the changed rotational speed to the output member.